Mortality risk increases with natal dispersal distance in American martens

Abstract

The assumption that mortality risk increases with dispersal distance has rarely been tested. We compared patterns of natal dispersal in the American marten (Martes americana) between a large regenerating forest landscape and an uncut landscape that was dominated by more mature forest to test whether mortality risk increased with dispersal distance, and whether variation in mortality risk influenced dispersal distance. Mortality risk increased with dispersal distance in both landscape treatments, but the distancedependent increase in mortality in the regenerating landscape was twice that in the uncut landscape. Differences in body condition, supported by other data on foraging efficiency, suggested that juveniles from the regenerating landscape were less able to cope with the energetic demands of dispersal compared with juveniles from older forests. Juveniles travelled shorter distances in the regenerating versus uncut landscape. These results implied that dispersal was costly in terms of juvenile survival and that mean dispersal distance was shaped, in part, by mortality risk.

The consequences of interactions between dispersal distance and resolution of habitat clustering for dispersal success

“…In addition, movement responses to habitat clustering may depend on whether movements are biased towards specific directions 90 (e.g.habitat) (Farnsworth and Beecham 1999). This is an important problem in landscape ecology because the fitness consequences of large dispersal distancesare different from the fitness consequences of small dispersal distances (Johnson et al 2009),with potential repercussions for the evolution of dispersal (Travis 2001). …”

Evaluating the relationship between trapper harvest of American martens (Martes americana) and the quantity and spatial configuration of habitat in the boreal forests of Ontario, Canada

“…Specifically, Chapin et al (1998) observed that non-resident martens selected much smaller patches of residual forest (>6 m in height) than resident martens, and Payer and Harrison (1999) found a similar but weaker relationship in home range-scale habitat selection between yearling and mature martens. If traplines with little suitable habitat were acting as sinks for juvenile animals, poor body condition (as observed by Johnson et al 2009) and increased vulnerability to trapping may have further undermined the relationship between trapper success and habitat quality. Repeating the current analyses using the number of adult martens trapped, or the ratio of juvenile to adult martens, as the dependent variable may result in a stronger association between trapper success and the quantity and spatial configuration of suitable habitat.…”

“…The traplines in our study were large (average of 160 km 2 to 190 km 2 ), suggesting that the number of juvenile martens trapped on a trapline should reflect recruitment on that trapline. However, given that average juvenile marten dispersal distances range from 4 km to 18 km (Broquet et al 2006a, Johnson et al 2009, it is plausible that on some traplines a significant proportion of harvested martens may have immigrated from adjacent areas, or still be in the process of dispersing (Johnson 2008). If resident or dispersing juvenile martens occupy traplines with lower-quality habitat than their adult counterparts, we would expect results similar to what we observed-only a weak relationship between the quantity and spatial configuration of suitable habitat and trapper success.…”

“…Research on the effects of landscape pattern on martens has shown that marten home ranges incorporate a high proportion (60%-75%) of mature forest, generally in patches that are larger than the average available on the landscape (Chapin et al 1998, Hargis et al 1999, Potvin et al 2000. Furthermore, it appears that dispersing juvenile martens suffer higher mortality rates in younger forests than in mature forests (Johnson et al 2009). However, with the exception of some conceptual models (e.g., Thompson and Harestad 1994) and simulation models (e.g., Schneider 1997), there is little empirical information to suggest how habitat should be distributed across large (100s to 1000s of km 2 ) landscapes.…”

Hidden dispersal in an urban world: genetic analysis reveals occasional long-distance dispersal and limited spatial substructure among Dutch pine martens

“…Pine martens show strong territoriality, resulting in large home ranges and high dispersal of, at least in the Netherlands , especially the juvenile males. Natal dispersal distances of up to 9 km in females and up to 181 km in males were reported for the related American marten (Martes americana; Johnson et al 2009), suggesting that occasional dispersal over [100 km may also occur in pine martens.…”